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Yes. Thanks Jim; Errington.
----- Original Message -----=20
From: Jim Wolford=20
To: Dave Webster=20
Sent: Thursday, September 11, 2014 1:33 AM
Subject: Fwd: [NatureNS] Brood parasites
Dave, Shouldn=92t =93Herrington=94 be =93Errington=94? Jim
Begin forwarded message:
From: David & Alison Webster <dwebster@glinx.com>
Subject: Re: [NatureNS] Brood parasites
Date: September 10, 2014 at 9:22:09 PM ADT
To: naturens@chebucto.ns.ca
Reply-To: naturens@chebucto.ns.ca
Hi James, Steve, Randy & All, Sept 10, 2014
This is a variation on the theme of predation so mechanisms of =
predation will apply.
And, as noted by Paul L. Herrington (The phenomenon of predation =
Amer. Sci.51(2):180-192, 1963) ""Nature's way is any way that works"". =
In this essay he condensed 60 years of vertebrate predation research to =
12 pages so the original has a high content/fluff ratio. But condensing =
further-- "I regard the outstanding source of error in appraisals of =
predator-prey relationships as confusion of the fact of predation with =
the effect of predation." and "Watch out for compensations in attempting =
to distinguish between what does and does not count."
All sorts of compensating adjustments can kick in but perhaps the =
most direct is reduction of intraspecific competition. With fewer host =
young in a given area, competing for finite resources, their survival =
rate will be increased.
But in any case, brood parasitism will tend to cull the offspring =
of potential parents who are less aware and, if this poor awareness has =
a genetic basis then, over many generations, awareness of the host =
species would improve.
Yt, Dave Webster, Kentville
----- Original Message -----
From: James Churchill
To: naturens
Sent: Tuesday, September 09, 2014 11:59 AM
Subject: Re: [NatureNS] Brood parasites
hi folks,=20
Here is a recent paper summarizing host defense against cowbird =
parisitism in North America:
HOST DEFENSES AGAINST COWBIRD (MOLOTHRUS SPP.)=20
PARASITISM: IMPLICATIONS FOR COWBIRD MANAGEMENT
Ornithological Monographs, 2005
=
http://www.biosci.missouri.edu/avianecology/courses/avianecology/readings=
/Peer_BD_2005.pdf
Note, this opens a pdf.
cheers,
On Tue, Sep 9, 2014 at 12:38 AM, Stephen Shaw<srshaw@dal.ca> wrote:
An interesting question is why host species at least in some cases =
do not take countermeasures to turf out the egg(s) of the parasite. At =
least in one case, it is not a problem of clever cryptic coloration =
having been used to evade detection. The single cuckoo species we used =
to see in UK often lays an egg in the nest of the hedge sparrow =
(dunnock). The single cuckoo egg is much larger than those of the =
dunnock, is often white with brown spots versus always plain bright blue =
for the dunnock. Some birds, perhaps most, have good colour vision so =
there should be no problem in detecting an alien egg that is also twice =
the size. The newly hatched cuckoo throws out all the dunnock's eggs, =
so the dunnock ends up not rearing any offspring of its own for that =
breeding cycle. This should be a strong evolutionary incentive to =
develop a defense.
Presumably there must be some disadvantage attached to developing =
a simple defense of detecting then removing an alien egg? I could see =
it if the parasite's eggs looked very similar to those of the host -- =
the defending host bird then might remove some of its own eggs by =
mistake, a disadvantage. At least for the UK cuckoo this is not the =
case: the eggs are easily distinguished from those of most host =
species'.
Is there a plausible explanation for this, and is it a general =
phenomenon? If parasitism of the dunnock by the cuckoo were a very =
recent development, it could be argued that the dunnock has not yet had =
time to evolve countermeasures, but this sounds a bit lame. Have any =
N. American brood parasites (cowbirds?) developed eggs that mimic those =
of their hosts -- is there a general rule for this, where the UK cuckoo =
is an exception? My guess is that 97% of the folk on NatureNS are =
birders of some ilk, so someone out there must have an answer.
As a related afterthought, bird books in the UK in the 50s-60s =
used to describe the nests, eggs and nesting habits of birds, not just =
their plumage. I haven't seen this here in the Sibley, Petersen etc =
recent era in Canada/USA or I could probably have answered the cowbird =
question myself. I presume the main (and valid) reasons are now to =
discourage any interest in egg-collecting or nest-disturbing, by simply =
not giving out any useful information?
Steve (Hfx)
________________________________________
From: naturens-owner@chebucto.ns.ca =
[naturens-owner@chebucto.ns.ca] on behalf of Randy Lauff =
[randy.lauff@gmail.com]
Sent: Monday, September 8, 2014 2:03 PM
To: NatureNS
Subject: Re: [NatureNS] Brood parasites
Our own Black-billed Cuckoo normally builds its own nest, but will =
sometimes brood parasitize other species.
They avoid wiping themselves out in the same way carnivores =
do...too many carnivores, not enough prey, many carnivores starve, prey =
rebounds, carnivores increase. This is a basic explanation...there's a =
lot to this.
Randy
_________________________________
RF Lauff
Way in the boonies of
Antigonish County, NS.
On 8 September 2014 13:49, Gerald =
<naturens@zdoit.airpost.net<mailto:naturens@zdoit.airpost.net>> wrote:
I hope brood parasites is the correct term for birds that lay =
their eggs
in the nest of a different species.
Are there such parasitic bird species who can also build their own
nests? How do they avoid becoming so successful that they wipe out =
the
hosts and thereby themselves?
--
Gerald
--=20
James Churchill
Kentville, Nova Scotia
jameslchurchill@gmail.com
(902) 681-2374
No virus found in this message.
Checked by AVG - www.avg.com
Version: 2014.0.4765 / Virus Database: 4015/8177 - Release Date: =
09/08/14
No virus found in this message.
Checked by AVG - www.avg.com
Version: 2014.0.4765 / Virus Database: 4015/8195 - Release Date: =
09/11/14
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charset="Windows-1252"
Content-Transfer-Encoding: quoted-printable
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META content=3D"text/html; charset=3Dwindows-1252" =
http-equiv=3DContent-Type>
<META name=3DGENERATOR content=3D"MSHTML 8.00.6001.23588">
<STYLE></STYLE>
</HEAD>
<BODY=20
style=3D"WORD-WRAP: break-word; -webkit-nbsp-mode: space; =
-webkit-line-break: after-white-space"=20
bgColor=3D#ffffff>
<DIV>Yes. Thanks Jim; Errington.</DIV>
<DIV style=3D"FONT: 10pt arial">----- Original Message -----=20
<DIV style=3D"BACKGROUND: #e4e4e4; font-color: black"><B>From:</B> <A=20
title=3Djimwolford@eastlink.ca =
href=3D"mailto:jimwolford@eastlink.ca">Jim=20
Wolford</A> </DIV>
<DIV><B>To:</B> <A title=3Ddwebster@glinx.com=20
href=3D"mailto:dwebster@glinx.com">Dave Webster</A> </DIV>
<DIV><B>Sent:</B> Thursday, September 11, 2014 1:33 AM</DIV>
<DIV><B>Subject:</B> Fwd: [NatureNS] Brood parasites</DIV></DIV>
<DIV><BR></DIV>Dave, Shouldn=92t =93Herrington=94 be =93Errington=94? =
Jim<BR>
<DIV><BR>
<DIV>Begin forwarded message:</DIV><BR =
class=3DApple-interchange-newline>
<BLOCKQUOTE type=3D"cite">
<DIV style=3D"MARGIN: 0px"><SPAN style=3D"FONT-FAMILY: =
'Helvetica'"><B>From:=20
</B></SPAN><SPAN style=3D"FONT-FAMILY: 'Helvetica'">David & Alison =
Webster=20
<<A=20
=
href=3D"mailto:dwebster@glinx.com">dwebster@glinx.com</A>><BR></SPAN><=
/DIV>
<DIV style=3D"MARGIN: 0px"><SPAN style=3D"FONT-FAMILY: =
'Helvetica'"><B>Subject:=20
</B></SPAN><SPAN style=3D"FONT-FAMILY: 'Helvetica'"><B>Re: [NatureNS] =
Brood=20
parasites</B><BR></SPAN></DIV>
<DIV style=3D"MARGIN: 0px"><SPAN style=3D"FONT-FAMILY: =
'Helvetica'"><B>Date:=20
</B></SPAN><SPAN style=3D"FONT-FAMILY: 'Helvetica'">September 10, 2014 =
at=20
9:22:09 PM ADT<BR></SPAN></DIV>
<DIV style=3D"MARGIN: 0px"><SPAN style=3D"FONT-FAMILY: =
'Helvetica'"><B>To:=20
</B></SPAN><SPAN style=3D"FONT-FAMILY: 'Helvetica'"><A=20
=
href=3D"mailto:naturens@chebucto.ns.ca">naturens@chebucto.ns.ca</A><BR></=
SPAN></DIV>
<DIV style=3D"MARGIN: 0px"><SPAN style=3D"FONT-FAMILY: =
'Helvetica'"><B>Reply-To:=20
</B></SPAN><SPAN style=3D"FONT-FAMILY: 'Helvetica'"><A=20
=
href=3D"mailto:naturens@chebucto.ns.ca">naturens@chebucto.ns.ca</A><BR></=
SPAN></DIV><BR>
<DIV>
<DIV=20
style=3D"TEXT-TRANSFORM: none; TEXT-INDENT: 0px; FONT: 12px Helvetica; =
WHITE-SPACE: normal; LETTER-SPACING: normal; WORD-SPACING: 0px; =
-webkit-text-stroke-width: 0px"=20
bgcolor=3D"#ffffff">
<DIV>Hi James, Steve, Randy & All, =20
=
=20
Sept 10, 2014</DIV>
<DIV> This is a variation on the theme of predation =
so=20
mechanisms of predation will apply.</DIV>
<DIV> </DIV>
<DIV>
<DIV> And, as noted by Paul L. Herrington (The=20
phenomenon of predation Amer. Sci.51(2):180-192, 1963) ""Nature's way =
is any=20
way that works"". In this essay he condensed 60 years of vertebrate =
predation=20
research to 12 pages so the original has a high content/fluff =
ratio. But=20
condensing further-- "I regard the outstanding source of error in =
appraisals of predator-prey relationships as confusion of the fact of=20
predation with the effect of predation." and "Watch out for =
compensations in=20
attempting to distinguish between what does and does not count."</DIV>
<DIV> </DIV>
<DIV> All sorts of compensating adjustments can kick =
in but=20
perhaps the most direct is reduction of intraspecific competition. =
With fewer=20
host young in a given area, competing for finite resources, their =
survival=20
rate will be increased.</DIV>
<DIV> </DIV>
<DIV> But in any case, brood parasitism will tend to =
cull=20
the offspring of potential parents who are less aware and, if this =
poor=20
awareness has a genetic basis then, over many generations, awareness =
of the=20
host species would improve.</DIV>
<DIV> </DIV>
<DIV>Yt, Dave Webster, Kentville</DIV></DIV>
<BLOCKQUOTE=20
style=3D"BORDER-LEFT: rgb(0,0,0) 2px solid; PADDING-LEFT: 5px; =
PADDING-RIGHT: 0px; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px"=20
dir=3Dltr>
<DIV style=3D"FONT: 10pt arial">----- Original Message -----</DIV>
<DIV=20
style=3D"BACKGROUND-COLOR: rgb(228,228,228); FONT: 10pt =
arial"><B>From:</B><SPAN=20
class=3DApple-converted-space> </SPAN><A =
title=3Djameslchurchill@gmail.com=20
href=3D"mailto:jameslchurchill@gmail.com">James Churchill</A></DIV>
<DIV style=3D"FONT: 10pt arial"><B>To:</B><SPAN=20
class=3DApple-converted-space> </SPAN><A =
title=3Dnaturens@chebucto.ns.ca=20
href=3D"mailto:naturens@chebucto.ns.ca">naturens</A></DIV>
<DIV style=3D"FONT: 10pt arial"><B>Sent:</B><SPAN=20
class=3DApple-converted-space> </SPAN>Tuesday, September 09, =
2014 11:59=20
AM</DIV>
<DIV style=3D"FONT: 10pt arial"><B>Subject:</B><SPAN=20
class=3DApple-converted-space> </SPAN>Re: [NatureNS] Brood=20
parasites</DIV>
<DIV><BR></DIV>
<DIV dir=3Dltr>hi folks,
<DIV><BR></DIV>
<DIV>Here is a recent paper summarizing host defense against cowbird =
parisitism in North America:</DIV>
<DIV><BR></DIV>
<DIV>HOST DEFENSES AGAINST COWBIRD (MOLOTHRUS SPP.)<SPAN=20
class=3DApple-converted-space> </SPAN><BR>PARASITISM: =
IMPLICATIONS FOR=20
COWBIRD MANAGEMENT<BR><BR>Ornithological Monographs, 2005<BR>
<DIV></DIV></DIV>
<DIV><A=20
=
href=3D"http://www.biosci.missouri.edu/avianecology/courses/avianecology/=
readings/Peer_BD_2005.pdf">http://www.biosci.missouri.edu/avianecology/co=
urses/avianecology/readings/Peer_BD_2005.pdf</A><BR></DIV>
<DIV><BR></DIV>
<DIV>Note, this opens a pdf.</DIV>
<DIV><BR></DIV>
<DIV>cheers,</DIV>
<DIV><BR></DIV>
<DIV><BR></DIV>
<DIV><BR></DIV>
<DIV>
<DIV class=3Dgmail_extra><BR>
<DIV class=3Dgmail_quote>On Tue, Sep 9, 2014 at 12:38 AM, Stephen =
Shaw<SPAN=20
dir=3Dltr><<A href=3D"mailto:srshaw@dal.ca"=20
target=3D_blank>srshaw@dal.ca</A>></SPAN><SPAN=20
class=3DApple-converted-space> </SPAN>wrote:<BR>
<BLOCKQUOTE=20
style=3D"BORDER-LEFT: rgb(204,204,204) 1px solid; MARGIN: 0px 0px =
0px 0.8ex; PADDING-LEFT: 1ex"=20
class=3Dgmail_quote>An interesting question is why host species at =
least in=20
some cases do not take countermeasures to turf out the egg(s) of =
the=20
parasite. At least in one case, it is not a problem of =
clever=20
cryptic coloration having been used to evade detection. The =
single=20
cuckoo species we used to see in UK often lays an egg in the nest =
of the=20
hedge sparrow (dunnock). The single cuckoo egg is much =
larger than=20
those of the dunnock, is often white with brown spots versus =
always plain=20
bright blue for the dunnock. Some birds, perhaps most, have =
good=20
colour vision so there should be no problem in detecting an alien =
egg that=20
is also twice the size. The newly hatched cuckoo throws out =
all the=20
dunnock's eggs, so the dunnock ends up not rearing any offspring =
of its=20
own for that breeding cycle. This should be a strong =
evolutionary=20
incentive to develop a defense.<BR><BR>Presumably there must be =
some=20
disadvantage attached to developing a simple defense of detecting =
then=20
removing an alien egg? I could see it if the parasite's eggs =
looked=20
very similar to those of the host -- the defending host bird then =
might=20
remove some of its own eggs by mistake, a disadvantage. At =
least for=20
the UK cuckoo this is not the case: the eggs are easily =
distinguished from=20
those of most host species'.<BR><BR>Is there a plausible =
explanation for=20
this, and is it a general phenomenon? If parasitism of the =
dunnock=20
by the cuckoo were a very recent development, it could be argued =
that the=20
dunnock has not yet had time to evolve countermeasures, but this =
sounds a=20
bit lame. Have any N. American brood parasites =
(cowbirds?)=20
developed eggs that mimic those of their hosts -- is there a =
general=20
rule for this, where the UK cuckoo is an exception? My guess =
is that=20
97% of the folk on NatureNS are birders of some ilk, so someone =
out there=20
must have an answer.<BR><BR>As a related afterthought, bird books =
in the=20
UK in the 50s-60s used to describe the nests, eggs and nesting =
habits of=20
birds, not just their plumage. I haven't seen this here in =
the=20
Sibley, Petersen etc recent era in Canada/USA or I could probably =
have=20
answered the cowbird question myself. I presume the =
main (and=20
valid) reasons are now to discourage any interest in =
egg-collecting or=20
nest-disturbing, by simply not giving out any useful =
information?<BR>Steve=20
(Hfx)<BR>________________________________________<BR>From:<SPAN=20
class=3DApple-converted-space> </SPAN><A=20
href=3D"mailto:naturens-owner@chebucto.ns.ca"=20
target=3D_blank>naturens-owner@chebucto.ns.ca</A><SPAN=20
class=3DApple-converted-space> </SPAN>[<A=20
href=3D"mailto:naturens-owner@chebucto.ns.ca"=20
target=3D_blank>naturens-owner@chebucto.ns.ca</A>] on behalf of =
Randy Lauff=20
[<A href=3D"mailto:randy.lauff@gmail.com"=20
target=3D_blank>randy.lauff@gmail.com</A>]<BR>Sent: Monday, =
September 8,=20
2014 2:03 PM<BR>To: NatureNS<BR>Subject: Re: [NatureNS] Brood=20
parasites<BR><BR>Our own Black-billed Cuckoo normally builds its =
own nest,=20
but will sometimes brood parasitize other species.<BR><BR>They =
avoid=20
wiping themselves out in the same way carnivores do...too many =
carnivores,=20
not enough prey, many carnivores starve, prey rebounds, carnivores =
increase. This is a basic explanation...there's a lot to=20
this.<BR><BR>Randy<BR><BR>_________________________________<BR>RF=20
Lauff<BR>Way in the boonies of<BR>Antigonish County, NS.<BR><BR>On =
8=20
September 2014 13:49, Gerald <<A=20
href=3D"mailto:naturens@zdoit.airpost.net"=20
target=3D_blank>naturens@zdoit.airpost.net</A><mailto:<A=20
href=3D"mailto:naturens@zdoit.airpost.net"=20
target=3D_blank>naturens@zdoit.airpost.net</A>>> wrote:<BR>I =
hope=20
brood parasites is the correct term for birds that lay their =
eggs<BR>in=20
the nest of a different species.<BR><BR>Are there such parasitic =
bird=20
species who can also build their own<BR>nests? How do they avoid =
becoming=20
so successful that they wipe out the<BR>hosts and thereby=20
themselves?<BR><BR>--<BR>Gerald<BR><BR></BLOCKQUOTE></DIV><BR><BR =
clear=3Dall>
<DIV><BR></DIV>--<SPAN =
class=3DApple-converted-space> </SPAN><BR>
<DIV dir=3Dltr>James Churchill<BR>Kentville, Nova Scotia<BR><A=20
href=3D"mailto:jameslchurchill@gmail.com"=20
target=3D_blank>jameslchurchill@gmail.com</A><BR><A=20
href=3D"tel:%28902%29%20681-2374" target=3D_blank =
value=3D"+19026812374">(902)=20
681-2374</A><BR><BR><BR><BR></DIV></DIV></DIV></DIV><A></A>
<P align=3Dleft avgcert??=3D"">No virus found in this =
message.<BR>Checked by AVG=20
-<SPAN class=3DApple-converted-space> </SPAN><A=20
href=3D"http://www.avg.com/">www.avg.com</A><BR>Version: 2014.0.4765 =
/ Virus=20
Database: 4015/8177 - Release Date:=20
09/08/14</P></BLOCKQUOTE></DIV></DIV></BLOCKQUOTE></DIV><BR><A></A>
<P align=3Dleft avgcert?? color=3D"#000000">No virus found in this=20
message.<BR>Checked by AVG - <A=20
href=3D"http://www.avg.com">www.avg.com</A><BR>Version: 2014.0.4765 / =
Virus=20
Database: 4015/8195 - Release Date: 09/11/14</P></BODY></HTML>
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